MAVEN: Mars Atmospheric Loss

on November 5, 2013

When you take a look at Mars, you probably wouldn't think that it looks like a nice place to live. It's dry, it's dusty, and there's practically no atmosphere. But some scientists think that Mars may have once looked like a much nicer place to live, with a thicker atmosphere, cloudy skies, and possibly even liquid water flowing over the surface. So how did Mars transform from a warm, wet world to a cold, barren desert? NASA's MAVEN spacecraft will give us a clearer idea of how Mars lost its atmosphere (and thus its water), and scientists think that several processes have had an impact.

SPUTTERING How did Mars, a once wet planet, lose its early atmosphere? One possibility is through a process called "sputtering," in which atoms are knocked away from the atmosphere due to impacts with energetic particles.

PLASMA PROCESSES Mars's thick early atmosphere was likely lost to space, and the Sun is a potential culprit. When high-energy solar photons strike the upper Martian atmosphere they can ionize gas molecules, causing the atmosphere to erode over time.